This invention relates to the field of balloon catheters, and more particularly, to the field of miniaturized detachable balloon catheters for use in human blood vessels.
It has become a rather routine procedure to use balloon catheters to occlude vessels in certain types of cardiovascular surgery. In this procedure, an inflatable balloon which is positioned on the distal end of a cannula is inserted into a blood vessel and is either manually directed to a desired position in a blood vessel or is allowed to move to a desired position by circulation of blood through the vessel. When the balloon is properly positioned, it is then inflated by a fluid, or by a solidifying filler material, until the sides of the balloon are in contact with the walls of the blood vessel. The cannula may then be detached and withdrawn from the balloon, and the balloon may be left in the blood vessel in order to occlude the blood vessel.
One problem with such prior art detachable balloon catheters is that it is very difficult to precisely control the force required to withdraw the cannula from the balloon. As may be appreciated, if this force is too great, the balloon may be dislodged or repositioned in the blood vessel during detachment of the cannula. If the force required to withdraw the cannula from the balloon is too small, the balloon may become prematurely detached from the cannula during positioning of the balloon within the blood vessel.
Still another problem with such prior balloon catheters is that if a non-solidifying filler material, such as saline solution, is utilized to inflate the balloon, leakage of this material often occurs through the seal of the mouth of the balloon when the cannula is withdrawn from the balloon.
Accordingly, an important objective of the present invention is to provide a miniaturized detachable balloon catheter which may be used for permanent occlusion of a blood vessel, but one in which a cannula retainer mechanism automatically detaches the cannula from the balloon upon inflation of the balloon thereby preventing premature detachment of the balloon from the catheter.
Another objective of the present invention is to provide a miniaturized balloon catheter and a method of using the balloon catheter which is efficient in operation and relatively easy and inexpensive to manufacture.